Controlled engine camshaft stopping position

• US 20060016411A1
• Filed: 07/21/2004
• Published: 01/26/2006
• Est. Priority Date: 07/21/2004
• Status: Active Grant

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Fischer, Thomas H., Kunz, Timothy W., Harris, Wayne S., Flanagan, Jason W.
• Granted Patent: US 7,066,127 B2
• Time in Patent Office: Days
• US Class Current: 123/179.300
• CPC Class Codes: F01L 1/047 Camshafts
• CPC Class Codes: F01L 1/24 by fluid means, e.g. hydraulically
• CPC Class Codes: F01L 1/46 Component parts, details, or accessories, not provided for in preceding subgroups
• CPC Class Codes: F01L 2800/03 Stopping; Stalling
• CPC Class Codes: F01L 2810/04 Reducing noise
• CPC Class Codes: F01L 2820/041 Camshafts position or phase sensors
• CPC Class Codes: F01L 2820/042 Crankshafts position
• CPC Class Codes: F02B 77/08 Safety, indicating or supervising devices thermal insulation F02B77/11; rendering engines inoperative or idling F02D17/04; dependent on lubricating conditions F01M1/22; dependent on cooling F01P11/14
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2041/0095 Synchronisation of the cylinders during engine shutdown
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02N 11/00 Starting of engines by means of electric motors
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 19/004 Aiding engine start by using decompression means or variable valve actuation
• CPC Class Codes: F02N 19/005 Aiding engine start by starting from a predetermined position, e.g. pre-positioning or reverse rotation
• CPC Class Codes: F02N 2019/008 the engine being stopped in a particular position

Abstract

A system for bringing an internal combustion engine to a stop at a predetermined angular position of an engine shaft, such as a crankshaft or a camshaft, with respect to the engine'"'"'s valves. The optimum shaft stop position is the point wherein the fewest lifters are collapsed the least amount. Exemplary methods and apparatus include using the engine starter motor to jog the stopped engine to the desired position; using the engine alternator to impose a variable electromagnetic load on the engine to bring the engine to a stop at the desired position; using variable firing of cylinders to control the deceleration profile to bring the engine to a stop at the desired position; and providing one or more detents formed in the shaft and using a shaft follower to control the stop position of the shaft by engaging the follower into a detent.

Claims

1. A system for causing an engine shaft in an internal combustion engine to stop after engine shutdown at a predetermined angular position of the shaft with respect to the engine'"'"'s valves, said system comprising:

a) a sensor for sensing the angular position of said shaft;

b) a programmable electronic engine control module in electrical communication with said sensor; and

c) a shaft positioning mechanism responsive to said engine control module for causing said shaft to stop at said predetermined angular position.

2. A system in accordance with claim 1 wherein said shaft positioning mechanism includes an electric motor engageable with said engine.

3. A system in accordance with claim 2 wherein said electric motor is a starter motor for said engine.

4. A system in accordance with claim 1 wherein said shaft positioning mechanism includes an alternator for said engine.

5. A system in accordance with claim 1 wherein said shaft positioning mechanism includes at least one selected combustion cylinder of said engine.

6. A system in accordance with claim 1 wherein said shaft positioning mechanism includes:

a) at least one detent associated with said shaft; and

b) a follower disposed adjacent said detent for selectively engaging therewith to stop said shaft in said predetermined position.

7. A system in accordance with claim 1 further comprising a variable valve activation system.

8. A system in accordance with claim 1 wherein said engine shaft is selected from a group consisting of a crankshaft and a camshaft.

9. A method for causing a shaft in an internal combustion engine to a stop at a predetermined angular position of the shaft with respect to the engine valves, said method comprising the steps of:

a) providing a sensor for sensing the angular position of said shaft;

b) providing a programmable electronic engine control module in electrical communication with said sensor;

c) providing a shaft positioning mechanism responsive to said engine control module for causing said shaft to stop at said predetermined angular orientation; and

d) engaging said shaft positioning mechanism to cause said shaft to stop at said predetermined angular position.

10. A method in accordance with claim 9 wherein said shaft positioning mechanism includes a starter motor for said engine.

11. A method in accordance with claim 9 wherein said shaft positioning mechanism includes an alternator for said engine.

12. A method in accordance with claim 9 wherein said shaft positioning mechanism includes at least one combustion cylinder of said engine.

13. A method in accordance with claim 9 wherein shaft positioning mechanism includes:

a) at least one detent associated with said shaft; and

b) a follower disposed adjacent said detent for selectively engaging therewith to stop said shaft in said predetermined position.

14. A vehicle comprising an internal combustion engine including a system for causing an engine shaft in said engine to a stop at a predetermined angular orientation of said shaft with respect to the engine'"'"'s valves, said system including:

a) a sensor for sensing the angular position of said shaft;

b) a programmable electronic engine control module in electrical communication with said sensor, and

c) a shaft positioning mechanism for causing said shaft to stop after engine shutdown at said predetermined angular orientation.

15. A method for reducing cold start engine noise when starting an internal combustion engine, comprising the steps of:

a) determining an optimum rotational position of an engine shaft in said engine wherein the number of valves open and the degree of valve opening is optimized, and wherein leakdown of hydraulic valve lifters associated with said open valves is optimized during shutdown periods of said engine; and

b) causing said shaft to stop at said optimum rotational position when said engine is shut down.